The invention proposes more particularly a method of manufacturing a hollow optical reflector of the type which comprises a rear body overmoulded around the convex rear external face of a front insert, the concave front internal face of which is covered (in particular at least partially) with a reflective coating, the method comprising:
a step of producing the insert by forming;
a step of overmoulding the body on the insert; and
a step of depositing the reflective layer on the concave front face of the insert (or on at least part of said face).
Such optical reflectors are generally used in the motor industry for manufacturing lights or headlights for equipping motor vehicles.
The reflective face of an optical reflector is generally concave and its generator is designed so as to obtain a light beam of given conformation.
Production of optical reflectors by moulding of a thermoplastic material, and then coating of the functional internal concave face with a reflective layer which is for example aluminium-based, are known.
However, when the surface of the mould is degraded, or else when it is not at an optimum temperature, the surface of the component obtained has irregularities and rough patches which, even after coating with the reflective layer, are detrimental to the quality of the light beam.
In order to remedy this problem, a proposal has been made to use a surfacer which fills in the various rough patches of the surface of the moulded component in order to form a smooth surface and which is next coated with the reflective layer.
However, when the reflective face has a complex shape, and it has sharp edges, the surfacer generally has a tendency to make these edges smoother, so that it also is detrimental to the quality of the light beam.
The document EP-A-0 727 677 proposes to produce the reflective face on an insert produced from a sheet of thermoformed plastic material, to overmould the body of the optical reflector on faces of the insert which are not intended to form the light beam, and then to coat the functional concave surface with the reflective layer.
The thermoforming of the plastic sheet makes it possible to have reflecting surfaces of very high quality and which are not impaired during moulding of the body. However, in the case of a complex reflecting surface, certain areas are sometimes difficult to access, so that the whole reflecting surface is not sufficiently fully covered by the reflective layer.